The aim of this work is to investigate the function of plastic clips which are used to join different parts, during mounting and dismounting processes. The clips are made of POM and will be mounted on steel plates. The study is undertaken using experimental and numerical methods. In experiments, the mounting and dismounting forces are measured with respect to vertical displacement of the clips related to the plate. The numerical method is performed using structural implicit non-linear quasi-static Finite Element method. In order to mesh, solve and study the results of FEM, Hyper Works, LS-DYNA and MD-Nastran programs are used. The effect of some parameters, e.g. stiffness, friction, hole diameter, etc. is also investigated and discussed. The project is done at SAAB Automobile AB.